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Chong, H., Tan, A., & Ng, G. (2007). Integrated cognitive architectures: a survey. Artificial Intelligence Review, 103-130.


@article{ChongTanNg2007,
author = {Chong, Hui-Qing and Tan, Ah-Hwee and Ng, Gee-Wah},
affiliation = {Nanyang Technological University School of Chemical and Biomedical Engineering Nanyang Avenue Singapore 639798 Singapore},
title = {Integrated cognitive architectures: a survey},
journal = {Artificial Intelligence Review},
publisher = {Springer Netherlands},
issn = {0269-2821},
keyword = {Computer Science},
pages = {103-130},
volume = {28},
issue = {2},
url = {http://dx.doi.org/10.1007/s10462-009-9094-9},
note = {10.1007/s10462-009-9094-9},
year = {2007}
}

Author of the summary: Lucas Stephenson, 2012, verdant.luke@gmail.com

The original paper is available online: http://www.springerlink.com/content/n30n8n46468210q7/

Cite this paper for:

Survey of 6 Cognitive Architectures

All 6 have been applied to a variety of cognitive tasks [p123]

SOAR is

“is one of the first cognitive architectures proposed” [p106]
Based on classical AI; it is learning and experience driven with a focus on problem solving. [p106]
SOAR is used for the understanding and incorporation of intelligent behaviour mechanisms in classical AI. [p106]

In SOAR

A flow diagram of the SOAR system is provided:


                    +---------------------------------------------+
                    |             Long Term Memories              |
  +------------+    |---------------------------------------------|
  | Learning   |    |+------------+  +-----------+  +------------+|
  | Mechanism  |<-->|| Procedural |  | Semantic  |  | Episodic   ||
  +------------+    || Memory     |  | Memory    |  | Memory     ||
                    |+--------+---+  +-----+-----+  +--+---------+|
  +------------+    |         |            |           |          |
  | Decision   |    |         v            v           v          |
  | Procedure  |<-->|      +-------------------------------+      |
  +------------+    |      |        Working Memory         |      |
                    |      +-----------------------+-------+      |
                    +--------------^---------------|--------------+
                                   |               |
                                   |               v
                            +------+-----+    +--------+
                            | Perception |    | Action |
                            +------------+    ++-------+
                                       ^       |
                                       |       v
                                   +---+---------+
                                   | Environment |
                                   +-------------+

The external environment state is made available through a perception module and can be influenced by implemented actions. [p106]
Long term memory stores procedural, semantic and episodic knowledge. [p106]
Working memory stores knowledge of goals, perceptions, hierarchy of states and operators relevant to current context. [p106]
Learning occurs when impasses arise; impasses are classified as no-change, tie, conflict, and rejection. [p107]
Learning occurs using chunking, reinforcement learning, episodic memory, and semantic memory techniques. [p107]

SOAR Applications

Used in problem solving task games, and by the US military for modeling, simulation and control. [p123]

ACT-R is

A system that uses empirical cognitive psychology data and brain imaging to model human cognition [p107]
Step by step understanding and prediction tool for human cognition systems. [p107]

In ACT-R

A flow diagram of the ACT-R system is provided:

    +--------------------+                         +------------------------+
    | Intentional Module |                         |  Declarative Module    |
    |  (not identified)  |                         | (temporal/hippocampus) |
    +--------+^----------+                         +---------+^-------------+
             ||                                              ||
      +------v+-------+                               +------v+----------+
      |  Goal Buffer  |                               | Retrieval Buffer |
      |    (DLPFC)    |    +-----------------------+  |     (VLPFC)      |
      +------+--------+    |     Productions       |  +-------+----------+
             +------------>|    (Basal Ganglia)    |<---------+
             +------------>+-----------------------+<---------+
             |             | Matching (Striatum)   |          |
             |             | Selection (Pallidum)  |          |
             |             | Execution (Thalamus)  |          |
             |             +-----------------------+          |
      +------+--------+                                 +-----+---------+
      | Visual Buffer |                                 | Manual Buffer |
      |  (Parietal)   |                                 |   (Motor)     |
      +------^+-------+                                 +----^+---------+
             ||                                              ||
     +-------+v--------+                              +------+v------------+
     |  Visual Module  |                              |   Manual Module    |
     | (Occipital etc) |                              | (Motor/Cerebellum) |
     +----------------^+                              ++-------------------+
                      |                                |
                     ++--------------------------------v+
                     |          Environment             |
                     +----------------------------------+

“The external environment and knowledge stored in the memories work conjunctively to select actions for execution to satisfy the goal(s) of the agent.” [p108]
As seen in the above figure, there are four basic modules, visual, manual, declarative memory and goals these are coordinated through the central production system, to enable cognition. [p108]
While the system is highly parallel it is limited to serial communication with each module, and the production system is only aware of the information in the serial buffers. [p108]
Buffers are limited to one declarative unit (chunk) at a time. [p109]
Procedural memory stores production rules and supports learning through production compilation. [p109]

ACT-R Applications

Framework for Tower of Hanoi, memory for text or lists of words, language comprehension, and communication. [p123]
Used for military aircraft control and brain activity prediction. [p123]
Used for HCI research [p124]

ICARUS is

A flow diagram of the ICARUS system is provided:

   +------------+
   | Long Term  |                    +--------------+
   | Conceptual |                    | Long Term    |
   | Memory     |                    | Skill Memory |
   +------^-----+                    +---+--------+-+
          |                              |        |
          |                              |        |
  +-------+--------+              +------v-----+ +v----------+
  | Categorisation |              | Skill      | | Means End |
  +----+-----^-----+       +------> Retrieval  | | Analysis  |
       |     |             |      +------+-----+ +----+------+
       |     |             |             |            |
 +-----v-----+-------+     |             |            |
 | Short Term        |     |          +--v------------v--+
 | Conceptual Memory +-----+          | Short Term Skill |
 | (Belief Memory)   |                | Memory           |
 +-------------------+                +------------------+
 | Perceptual Buffer |                | Motor Buffer     |
 +--------^----------+                +--------+---------+
          |                                    |
          |                                    |
    +-----+-------+                   +--------v--------+
    | Perception  <--+                | Skill Execution |
    +-------------+  |                +--+--------------+
                     |            +------+
                     |            |
                    ++------------v-+
                    |  Environment  |
                    +---------------+
Rooted in physical and embodied agents, integrates perception and action with cognition. [p109]
A goal is to learn and use symbolic structures as numeric utilities. [p109]
Distinct because of:
“(1) Cognitive reality of physical objects; (2) Cognitive separation of categories and skills; (3) Primacy of categorization and skill execution; (4) Hierarchical organization of long term memory; (5) Correspondence of long term or short term structure; and (6) Modulation of symbolic structures with utility functions.” [p109]
Has 4 main components; the perceptual buffer, the conceptual memory, the skill memory, and the motor buffer. [p109]

In ICARUS

The 4 main modules are [p110-111]

ICARUS Applications

“ICARUS has been applied to many cognitive tasks, including the Tower of Hanoi, multi-column subtraction, and peg solitaire. Other key domains, which have been studied to date, include in-city driving and pole balancing.” [p125]

BDI is

A flow diagram of BDI is included:

                +---------------------------+
                |         Database          |
                |---------------------------|
                |+--------------++---------+|
                || Plan Library || Beliefs ||
                |+-----+--------++---+-----+|
                +------|-------------|------+
                Plan as|          +--+
                Recipe |          |      Instansiated Plans
                      +v----------v---+      +------------+
    +---------+       |               <------> Intentions |
    | Desires +------->  Interpreter  |      +------------+
    +---------+  +---->               |  Selected Intentions
                 |    ++------------+-+
           Events|     |  Internal  |
                 |     |  Actions   |
          +------+-----v+           |
          | Event Queue |           |
          +--------^----+        +--v---------------+
                   |             | External Actions |
           +-------+----+        +--+---------------+
           | Perception |           |
           +----^-------+           |
                |                   |
                |                   |
                |      +------------v--+
                +------+  Environment  |
                       +---------------+
Based on intentional systems and human practical reasoning theories. [p111]
Real-time system and thus less process time for planning and reasoning. [p111]
A BDI agent can react to context changes and communicate to reach goals. [p111]

In BDI

“The body of a plan comprises of possible courses of actions and procedures to achieve a goal” [p111]
The term desires refers to non-conflicted goals. [p112]
Intentions are a set of action used in a desire attempt. [p112]
The system evaluates context each cycle, and formulates new desires and plans to complete them. [p112]
Means-end reasoning is used in the context of the current intention, to reduce reasoning time. [p112]
Learning is not classically integrated, but others have presented ways to incorporate learning. [p113]

BDI Applications

Originally designed for the reaction control system (RCS) in space shuttles. [p125]
Factory process control and business process management. [p125]
Performing cognitive tasks, such as the Tower of Hanoi. [p125]
Embodied conversational agents able to make small talk conversation and provide information. [p125]

The Subsumption Architecture is

Derived from behaviour-based robotics. [p113]
Decomposes problems based on behaviours exhibited while solving those tasks. [p113]

In The Subsumption Architecture

A hierarchy of competency layers with global access to context and allows parallel execution of behaviours. [p113]
A flow diagram of the subsumption architecture is included:

  +                   +
  +    +---------+    +
  +--->| Level 3 +------+
  |    +---------+      |
  |                     |
  |    +---------+      |
  +--->| Level 2 +------v---+
  |    +---------+          |
  |                         |
  |    +----------+         |
  +--->| Level 1  +---------v---+
  |    +----------+             |
  |                             |
  |    +----------+             |
  +--->| Level 0  +-------------v---+
  |    +----------+                 |
  |                                 |
  |                                 |
  |                                 |
  |                                 |
 +---------+                  +-----v-----+
 | Sensors |                  | Actuators |
 +-----^---+                  +---+-------+
       |                          |
     +-+--------------------------v-+
     |         Environment          |
     +------------------------------+
Each layer attempts to reach a goal, while being subsumed by higher level layers. [113]
Simpler development, testing of individual layers, additionally independent actions allow for rapidly changing environments to negatively impact the system less. [p113]
No explicit knowledge representation, each layer responsible for consuming data and reacting to it [p114]

The Subsumption Architecture Applications

Some examples include Robots with basic navigation abilities, market simulation in games, reactive musical accompanist, co-ordinated soccer playing in RoboCup. [p125]

CLARION is

A hybrid architecture that uses both implicit (procedural, neural net learned) and explicit memories for reasoning and learning. [p114]
“able to react in a dynamically changing environment without any pre-existing knowledge installed into the architecture.” [p114]

In CLARION

A flow diagram of the CLARION is included:

                      Top Level
      +---------------------------------------+
      |+--------------+       +--------------+|
      ||  Explicit    |       |  Explicit    ||
   +-->|Representation|       |Representation|<--+
   |  +--^--^------+-----------------------^--+  |
   |   | |  |      |  |       |            | |   |
   |   | |  |      +--------------------+  | |   |
   |   | |  |         |       |         |  | |   |
   |   | |  +-------------------+       |  | |   |
   |  +--v----------------------+-------v--v--+  |
   |  ||  Implicit    |       |  Implicit    ||  |
   +-->|Representation|       |Representation|<--+
   |  |+--------------+       +--------------+|  |
   |  +---------------------------------------+  |
   |                Bottom Level                 |
   |                                             |
   |                                             |
   |   +------------+             +---------+    |
   +---+ Perception |<--+    +----+ Actions +----+
       +------------+   |    |    +---------+
                        |    |
                        |    v
                   +----+----------+
                   |  Environment  |
                   +---------------+

Note that the dual Explicit/Implicit sections refer to the action centered (ACS) and the non-action centered subsystem (NACS) to account for variability in representation of explicit and implicit knowledge. [p115]
There are two levels, for the implicit and explicit knowledge and associated mechanisms; both layers are referenced during reasoning. [p115]
There are two subsystem not included in the diagram that motivate and control the system. [p115]
Rule based and similarity based reasoning are both used. [p116]
Learning can occur through procedural skills reinforcement or through explicit knowledge manipulation [p116]

CLARION Applications

“CLARION has been used in both the simulation of navigation and cognitive tasks.” [p125]
“The cognitive tasks using CLARION include serial reaction tasks, artificial grammar learning tasks, process control tasks, alphabetical arithmetic tasks, and the Tower of Hanoi.” [p125]

Conclusion

With the exception of the subsumption architecture, problem solving, reasoning/inference, and learning are essential components of most cognitive systems. [p126]
Many architectures use working memory in order to provide a manageable problem workspace incorporating the environment and relevant long term memory knowledge. [p126]
Most of the architectures use rules to dictate the actions that will be performed by the system. [p126]
Most of the architectures identify procedural (situational actions) and declarative (facts/inference rules] knowledge independently. [p126]
CLARION additionally includes episodic memory, could have more capacity to emulate human cognition. [p127]

Interesting Research Areas

Summary author's notes:


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